/*
 * MD4 hash implementation
 * Copyright (c) 2006, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "crypto.h"


#ifdef INTERNAL_MD4

#define        MD4_BLOCK_LENGTH                64
#define        MD4_DIGEST_LENGTH                16

typedef struct MD4Context {
        u32 state[4];                        /* state */
        u64 count;                        /* number of bits, mod 2^64 */
        u8 buffer[MD4_BLOCK_LENGTH];        /* input buffer */
} MD4_CTX;


static void MD4Init(MD4_CTX *ctx);
static void MD4Update(MD4_CTX *ctx, const unsigned char *input, size_t len);
static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx);


void md4_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
        MD4_CTX ctx;
        size_t i;

        MD4Init(&ctx);
        for (i = 0; i < num_elem; i++)
                MD4Update(&ctx, addr[i], len[i]);
        MD4Final(mac, &ctx);
}


/* ===== start - public domain MD4 implementation ===== */
/*        $OpenBSD: md4.c,v 1.7 2005/08/08 08:05:35 espie Exp $        */

/*
 * This code implements the MD4 message-digest algorithm.
 * The algorithm is due to Ron Rivest.        This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 * Todd C. Miller modified the MD5 code to do MD4 based on RFC 1186.
 *
 * Equivalent code is available from RSA Data Security, Inc.
 * This code has been tested against that, and is equivalent,
 * except that you don't need to include two pages of legalese
 * with every copy.
 *
 * To compute the message digest of a chunk of bytes, declare an
 * MD4Context structure, pass it to MD4Init, call MD4Update as
 * needed on buffers full of bytes, and then call MD4Final, which
 * will fill a supplied 16-byte array with the digest.
 */

#define        MD4_DIGEST_STRING_LENGTH        (MD4_DIGEST_LENGTH * 2 + 1)


static void
MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH]);

#define PUT_64BIT_LE(cp, value) do {                                        \
        (cp)[7] = (value) >> 56;                                        \
        (cp)[6] = (value) >> 48;                                        \
        (cp)[5] = (value) >> 40;                                        \
        (cp)[4] = (value) >> 32;                                        \
        (cp)[3] = (value) >> 24;                                        \
        (cp)[2] = (value) >> 16;                                        \
        (cp)[1] = (value) >> 8;                                                \
        (cp)[0] = (value); } while (0)

#define PUT_32BIT_LE(cp, value) do {                                        \
        (cp)[3] = (value) >> 24;                                        \
        (cp)[2] = (value) >> 16;                                        \
        (cp)[1] = (value) >> 8;                                                \
        (cp)[0] = (value); } while (0)

static u8 PADDING[MD4_BLOCK_LENGTH] = {
        0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/*
 * Start MD4 accumulation.
 * Set bit count to 0 and buffer to mysterious initialization constants.
 */
static void MD4Init(MD4_CTX *ctx)
{
        ctx->count = 0;
        ctx->state[0] = 0x67452301;
        ctx->state[1] = 0xefcdab89;
        ctx->state[2] = 0x98badcfe;
        ctx->state[3] = 0x10325476;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static void MD4Update(MD4_CTX *ctx, const unsigned char *input, size_t len)
{
        size_t have, need;

        /* Check how many bytes we already have and how many more we need. */
        have = (size_t)((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
        need = MD4_BLOCK_LENGTH - have;

        /* Update bitcount */
        ctx->count += (u64)len << 3;

        if (len >= need) {
                if (have != 0) {
                        os_memcpy(ctx->buffer + have, input, need);
                        MD4Transform(ctx->state, ctx->buffer);
                        input += need;
                        len -= need;
                        have = 0;
                }

                /* Process data in MD4_BLOCK_LENGTH-byte chunks. */
                while (len >= MD4_BLOCK_LENGTH) {
                        MD4Transform(ctx->state, input);
                        input += MD4_BLOCK_LENGTH;
                        len -= MD4_BLOCK_LENGTH;
                }
        }

        /* Handle any remaining bytes of data. */
        if (len != 0)
                os_memcpy(ctx->buffer + have, input, len);
}

/*
 * Pad pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
static void MD4Pad(MD4_CTX *ctx)
{
        u8 count[8];
        size_t padlen;

        /* Convert count to 8 bytes in little endian order. */
        PUT_64BIT_LE(count, ctx->count);

        /* Pad out to 56 mod 64. */
        padlen = MD4_BLOCK_LENGTH -
            ((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
        if (padlen < 1 + 8)
                padlen += MD4_BLOCK_LENGTH;
        MD4Update(ctx, PADDING, padlen - 8);                /* padlen - 8 <= 64 */
        MD4Update(ctx, count, 8);
}

/*
 * Final wrapup--call MD4Pad, fill in digest and zero out ctx.
 */
static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx)
{
        int i;

        MD4Pad(ctx);
        if (digest != NULL) {
                for (i = 0; i < 4; i++)
                        PUT_32BIT_LE(digest + i * 4, ctx->state[i]);
                os_memset(ctx, 0, sizeof(*ctx));
        }
}


/* The three core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) ((x & y) | (x & z) | (y & z))
#define F3(x, y, z) (x ^ y ^ z)

/* This is the central step in the MD4 algorithm. */
#define MD4STEP(f, w, x, y, z, data, s) \
        ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s) )

/*
 * The core of the MD4 algorithm, this alters an existing MD4 hash to
 * reflect the addition of 16 longwords of new data.  MD4Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void
MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH])
{
        u32 a, b, c, d, in[MD4_BLOCK_LENGTH / 4];

#if BYTE_ORDER == LITTLE_ENDIAN
        os_memcpy(in, block, sizeof(in));
#else
        for (a = 0; a < MD4_BLOCK_LENGTH / 4; a++) {
                in[a] = (u32)(
                    (u32)(block[a * 4 + 0]) |
                    (u32)(block[a * 4 + 1]) <<  8 |
                    (u32)(block[a * 4 + 2]) << 16 |
                    (u32)(block[a * 4 + 3]) << 24);
        }
#endif

        a = state[0];
        b = state[1];
        c = state[2];
        d = state[3];

        MD4STEP(F1, a, b, c, d, in[ 0],  3);
        MD4STEP(F1, d, a, b, c, in[ 1],  7);
        MD4STEP(F1, c, d, a, b, in[ 2], 11);
        MD4STEP(F1, b, c, d, a, in[ 3], 19);
        MD4STEP(F1, a, b, c, d, in[ 4],  3);
        MD4STEP(F1, d, a, b, c, in[ 5],  7);
        MD4STEP(F1, c, d, a, b, in[ 6], 11);
        MD4STEP(F1, b, c, d, a, in[ 7], 19);
        MD4STEP(F1, a, b, c, d, in[ 8],  3);
        MD4STEP(F1, d, a, b, c, in[ 9],  7);
        MD4STEP(F1, c, d, a, b, in[10], 11);
        MD4STEP(F1, b, c, d, a, in[11], 19);
        MD4STEP(F1, a, b, c, d, in[12],  3);
        MD4STEP(F1, d, a, b, c, in[13],  7);
        MD4STEP(F1, c, d, a, b, in[14], 11);
        MD4STEP(F1, b, c, d, a, in[15], 19);

        MD4STEP(F2, a, b, c, d, in[ 0] + 0x5a827999,  3);
        MD4STEP(F2, d, a, b, c, in[ 4] + 0x5a827999,  5);
        MD4STEP(F2, c, d, a, b, in[ 8] + 0x5a827999,  9);
        MD4STEP(F2, b, c, d, a, in[12] + 0x5a827999, 13);
        MD4STEP(F2, a, b, c, d, in[ 1] + 0x5a827999,  3);
        MD4STEP(F2, d, a, b, c, in[ 5] + 0x5a827999,  5);
        MD4STEP(F2, c, d, a, b, in[ 9] + 0x5a827999,  9);
        MD4STEP(F2, b, c, d, a, in[13] + 0x5a827999, 13);
        MD4STEP(F2, a, b, c, d, in[ 2] + 0x5a827999,  3);
        MD4STEP(F2, d, a, b, c, in[ 6] + 0x5a827999,  5);
        MD4STEP(F2, c, d, a, b, in[10] + 0x5a827999,  9);
        MD4STEP(F2, b, c, d, a, in[14] + 0x5a827999, 13);
        MD4STEP(F2, a, b, c, d, in[ 3] + 0x5a827999,  3);
        MD4STEP(F2, d, a, b, c, in[ 7] + 0x5a827999,  5);
        MD4STEP(F2, c, d, a, b, in[11] + 0x5a827999,  9);
        MD4STEP(F2, b, c, d, a, in[15] + 0x5a827999, 13);

        MD4STEP(F3, a, b, c, d, in[ 0] + 0x6ed9eba1,  3);
        MD4STEP(F3, d, a, b, c, in[ 8] + 0x6ed9eba1,  9);
        MD4STEP(F3, c, d, a, b, in[ 4] + 0x6ed9eba1, 11);
        MD4STEP(F3, b, c, d, a, in[12] + 0x6ed9eba1, 15);
        MD4STEP(F3, a, b, c, d, in[ 2] + 0x6ed9eba1,  3);
        MD4STEP(F3, d, a, b, c, in[10] + 0x6ed9eba1,  9);
        MD4STEP(F3, c, d, a, b, in[ 6] + 0x6ed9eba1, 11);
        MD4STEP(F3, b, c, d, a, in[14] + 0x6ed9eba1, 15);
        MD4STEP(F3, a, b, c, d, in[ 1] + 0x6ed9eba1,  3);
        MD4STEP(F3, d, a, b, c, in[ 9] + 0x6ed9eba1,  9);
        MD4STEP(F3, c, d, a, b, in[ 5] + 0x6ed9eba1, 11);
        MD4STEP(F3, b, c, d, a, in[13] + 0x6ed9eba1, 15);
        MD4STEP(F3, a, b, c, d, in[ 3] + 0x6ed9eba1,  3);
        MD4STEP(F3, d, a, b, c, in[11] + 0x6ed9eba1,  9);
        MD4STEP(F3, c, d, a, b, in[ 7] + 0x6ed9eba1, 11);
        MD4STEP(F3, b, c, d, a, in[15] + 0x6ed9eba1, 15);

        state[0] += a;
        state[1] += b;
        state[2] += c;
        state[3] += d;
}
/* ===== end - public domain MD4 implementation ===== */

#endif /* INTERNAL_MD4 */
